This invention relates to the field of digital image processing technology for typical use with digital photoprinters that read film images photoelectrically to produce prints (photographs) reproducing the images. More particularly, the invention relates to an image processing method that is capable of effective correction of the xe2x80x9cred eyexe2x80x9d problem with human subjects taken with the aid of an electronic flash.
Heretofore, the images recorded on photographic films such as negatives and reversals (which are hereunder referred to simply as xe2x80x9cfilmsxe2x80x9d) have been commonly printed on light-sensitive materials (photographic paper) by means of direct (analog) exposure in which the film image is projected onto the light-sensitive material to achieve its areal exposure.
A new technology has recently been introduced and this is a printer that relies upon digital exposure. Briefly, the image recorded on a film is read photoelectrically, converted to digital signals and subjected to various image processing operations to produce image data for recording purposes; recording light that has been modulated in accordance with the image data is used to scan and expose a light-sensitive material to record a latent image, which is subsequently developed to produce a (finished) print. The printer operating on this principle has been commercialized as a digital photoprinter.
In the digital photoprinter, images are converted to digital image data which are processed to determine the exposing conditions for printing. Hence, the digital photoprinter is capable of performing effective image processing operations such as the correction of washed-out highlights or flat shadows due to the taking of pictures with back light or an electronic flash, sharpening and the correction of under- or over-exposure and this enables the production of high-quality prints that have been impossible to attain by the conventional direct exposure technique. In addition, not only the assembling of plural images and the dividing of a single image but also the compositing of characters on image can be performed by processing the image data and, as a result, prints can be outputted after various editing and/or processing operations have been performed in accordance with specific uses. Outputting images as prints (photographs) is not the sole capability of the digital photoprinter; the image data can be supplied into a computer or the like and stored in recording media such as a floppy disk; hence, the image data can be put to various non-photographic uses.
Having these features, the digital photoprinter is basically composed of the following units: a scanner (image reading apparatus) that reads the image on a film photoelectrically; an image processing apparatus that processes the captured image to determine the exposing conditions for recording the image; and a printer (an image recording apparatus) that scan exposes a light-sensitive material in accordance with the determined exposing conditions and which then performs development and other necessary processing to produce prints.
In the scanner, reading light issuing from a light source is allowed to be incident on a film, from which projected light bearing the image recorded on the film is produced and focused by an imaging lens to form a sharp image on an image sensor such as a CCD sensor; the image is then captured by photoelectric conversion and sent to the image processing apparatus as image data for the film (i.e., image data signals) after being optionally subjected to various image processing steps.
In the image processing apparatus, image processing conditions are set on the basis of the image data captured with the scanner and image processing as determined by the thus set conditions is performed on the captured image data and the resulting output image data for image recording (i.e., exposing conditions) are sent to the printer.
In the printer, if it is of a type that relies upon exposure by scanning with an optical beam, the latter is modulated in accordance with the image data sent from the image processing apparatus and deflected in a main scanning direction as the light-sensitive material is transported in an auxiliary scanning direction perpendicular to the main scanning direction, whereby a latent image is formed as the result of exposure (printing) of the light-sensitive material with the image bearing optical beam. Development and other processing as determined by the light-sensitive material are then performed to produce a print (photograph) reproducing the image that was recorded on the film.
With prints such as portraits that contain human subjects in the image, the most important factor to the image quality is how fine the human subject is finished. Therefore, the phenomenon of xe2x80x9cred eyexe2x80x9d in which the eyes (or pupils) of a human subject appears red due, for example, to the reflection of light from an electronic flash used in shooting is a serious problem indeed.
As already mentioned, the image processing apparatus of the digital photoprinter produces image data for output by performing image processing on the image data captured with the scanner. This means that an appropriate image can be output by modifying the red eye through image data processing. A known method of correcting the red eye problem is by using a commercial image processing tool such as PhotoRetouch to extract the image data on the eye region of an image of interest and perform a processing scheme such as transforming the color of the eyes (i.e., the image data on them).
To perform this conventional process of red eye correction, it is necessary that the occurrence of red eye in a particular image (or frame) be already known. Therefore, in reprinting (remaking) a simultaneous print having the red eye problem, the conventional process of red eye correction is suitable for outputting prints in which the red eye is adequately corrected. On the other hand, in the case of processing a film from which prints are to be prepared for the first time (e.g. simultaneous prints) in large volumes and in an efficient way, it is extremely difficult to ensure positive correction of the red eye that has occurred. From a practical viewpoint, it is almost impossible to make simultaneous prints and yet perform red eye correction so that prints without the red eye problem can be output in a consistent manner.
The present invention has been accomplished under these circumstances and has as an object providing a digital image processing method in which the image recorded in a photographic film is captured photoelectrically and the obtained image data is subjected to specified image processing schemes to produce image data for output, and which is capable of effective red eye correction during the making of simultaneous prints so that high-quality images without the red-eye problem can be output in a consistent manner.
The stated object of the invention can be attained by an image processing method comprising the steps of performing prescan for capturing an image on a film at low resolution, determining image processing conditions using image data obtained by prescan, performing fine scan for capturing the image on the film at high resolution, and obtaining output image data by processing fine scanned image data in accordance with the image processing conditions, characterized in that the image captured with the prescan is represented on a display and used to select a frame or frames to be subjected to red eye correction, red eye correcting conditions for the thus selected frame or frames are set based on the fine scanned data and said selected frame or frames are subjected to said red eye correction in accordance with said red eye correcting conditions.
In a preferred embodiment, said fine scan is performed after all frames of the film have ended prescan and the frame or frames designated for said red eye correction is subjected to fine scan before any other frames or, alternatively, all frames are fine scanned consecutively.
In another preferred embodiment, either the fine scanned image data or the prescanned image data or both are used to represent a result of the red eye correction on the display.
In yet another preferred embodiment, image data for index prints is prepared using the prescanned data and the prescanned data that has been subjected to the red eye correction is used to prepare the index prints for the frame or frames that have been designated for the red eye correction.
One of preferable examples of the image processing method of the invention has following constituents.
The prescan performing step, the determining step, a step of representing a plurality of the prescan captured images of the frames on the display after all frames of the film have ended the prescan, and a step of selecting and designating a frame to be subjected to the red eye correction among the represented frames on the display are carried out in order.
One of a process for performing the red eye correction on the designated frame and a step of performing verification based on the prescanned image data on a frame not designated is repeated from a first frame to a last frame on the film.
The red eye correction process comprises a step of performing the fine scan on the designated frame to obtain the fine scan image data, a step of representing the image of the designated frame on the display based on the thus obtained fine scan image data, a step of setting the red eye correcting conditions for the designated frame, a step of subjecting the designated image to the red eye correction based on the fine scanned image data according to the red eye correcting conditions, a step of subjecting the designated image to the red eye correction based on the prescanned image data according to the red eye correcting conditions, a step of representing the image of the designated frame subjected to the red eye correction based on the prescanned image data on the display and a step of subjecting the image of the represented and designated frame based on the prescanned image data to the verification other than red eye.
All of the frames not designated are subjected to the fine scan from the frame of one end of the film to the frame of another end of the film after the frame of the one end of the film is returned to a start position.
In another preferable example of the present invention, the prescan performing step, the determining step and the prescan image representing step are carried out in the same way to the above example. Thereafter, in the selecting and designating steps, (all) frames to be subjected to the red eye correction are previously selected and designated on the one screen of the display (monitor).
Next, a plurality of the frames represented on the one screen of the display are subjected to the verification processing, and then the fine scan of the plurality of the frames of the one screen is started.
After the designated frame is subjected to the fine scan to obtain the fine scan image data, the fine scan image data of the designated frame is represented on the display. The red eye correction is performed on the represented frame on the display.
The reset of frame or frames which is not designated is subjected to the fine scan, if the there is the rest.
The other preferable example of the present invention is similar to the another preferable example up to the starting of the fine scan.
In this example, the frame or frames to be subjected to the red eye correction is not subjected to the fine scan.
After the verification and the fine scan of all frames of one case (one film) end, the frame of the one end of the film is returned to the start position.
Thereafter, only the designated frame to be subjected to the red eye correction is subjected to the fine scan, the fine scan image data of the designated frame is represented on the display, and the red eye correction is performed on the represented frame on the display.